This invention generally relates to the art of electrical connectors and, particularly, to a connecting device for establishing electrical communication between a pair of circuit boards.
Connection devices have been provided for connecting a pair of circuit boards to establish electrical communication between an upper circuit board and a grounding pad of a lower circuit board, for instance. An example of such a device is shown in U.S. Pat. No. 6,065,977, dated May 23, 2000, which is based on Japanese Application 9-227250.
The connection device shown in the above patent includes an insulating housing having an integral spacer portion disposed between the upper circuit board and the lower circuit board. An electrically conductive metal member has an upper plate sandwiched between the upper circuit board and an upper surface of the spacer portion, and a lower plate sandwiched between the lower circuit board and a lower surface of the spacer portion. Electrical connection is established between the upper and lower plates and grounding pads on the upper and lower circuit boards, respectively. Fastening means in the form of a bolt extends through the upper and lower circuit boards and the spacer portion, as well as through both the upper and lower plates of the electrically conductive metal member. Therefore, the spacer portion is clamped between the upper and lower plates of the conductive metal member. This connection device is mounted on the lower circuit board and, therefore, a recessed area of the spacer portion accommodates the lower plate so that the lower plate is generally flush with the bottom of the spacer portion.
Problems are encountered with connection devices as described above. First of all, since the fastening bolt extends through holes in both the upper plate and the lower plate of the conductive metal member, relatively expensive precision machining must be performed so that the through holes in the upper and lower plates are in strict alignment for receiving the bolt so that insertion of the bolt does not misalign the plates. Another problem concerns the dimensional relationship between the spacer portion and the conductive metal member. Specifically, if the spacer portion is bowed relative to the insulating housing due to external factors, such as heat or the like, the plates of the conductive metal member may move with the spacer portion and destroy flush surface relationship of the plates with the circuit boards which would make it impossible to establish good electrical communication between the plates and the grounding pads of the board. At least, abnormal stresses are created in the solder connections.
The present invention is directed to providing a new and improved electrically conductive metal member in the form of a connection device as described above, and avoiding the various problems associated therewith.
An object, therefore, of the invention is to provide a new and improved connection device for connecting a pair of circuit boards.
In the exemplary embodiment of the invention, the connection device includes a dielectric housing having a spacer portion for positioning between an upper circuit board and a lower circuit board. A conductive metal connecting member includes an upper plate portion sandwiched between the upper circuit board and an upper surface of the spacer portion, a lower plate portion sandwiched between the lower circuit board and a lower surface of the spacer portion, and a connecting portion connecting the upper and lower plate portions. A fastener extends through the circuit boards and the spacer portion. The upper plate portion is engageable with a conductive pad on the upper circuit board and includes a hole through which the fastener extends. The lower plate portion is engageable with a conductive pad on the lower circuit board and is disposed to one side away from the fastener. Therefore, the fastener does not extend through both the upper plate portion and the lower plate portion and avoids many of the problems of the prior art.
As disclosed herein, the fastener comprises a bolt. The conductive metal connecting member is generally C-shaped. The housing, including the spacer portion, has a bottom face for mounting on the lower circuit board, and the spacer portion includes a recessed area for receiving the lower plate portion with a lower surface thereof being generally flush with the bottom face of the spacer portion.
Another feature of the invention includes complementary interengaging latch means between the connecting member and the housing at the spacer portion. The latch means herein is provided by a latch hole in one of the upper and lower plate portions for receiving a latch boss on the spacer portion of the housing. In the illustrated embodiment herein, both the upper and lower plate portions have latch holes for receiving latch bosses on the top and bottom of the spacer portion.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.